With the proliferation of ballistic missile technology and the ever increasing accuracy of those missiles,ballistic missile defence has emerged as an important capability.
British forces do not yet have an operational anti-ballistic missile capability.
It is worth considering whether they need one.
For the United Kingdom,ballistic missile threats can be broken down into the following categories:
Strategic nuclear missiles;
Theatre range land attack ballistic missiles;
Theatre range ship attack ballistic missiles.
Strategic nuclear missiles are deterred by the United Kingdom's strategic nuclear detterent.
Hence there is little need for a anti-ballistic missile system to protect against strategic threats.
Theatre range land attack ballistic missiles primarily pose a threat to large,high value fixed installations.
Smaller targets are easier to disperse,conceal and protect and generally of lower value and consequently not worth the expenditure of a long range missile.
The most vulnerable of high value installations is the air base.
Aircraft are expensive and difficult to protect,particularly the larger transport and support types.
They also rely on large runways and parking areas which are easy targets for ballistic missiles.
Ballistic missiles are a highly likely,highly cost effective and highly combat effective threat to fixed air bases.
A ballistic missile defence system will be essential if the United Kingdom wishes to use land based aircraft from airfields within 2,000 miles of a ballistic missile armed opponent during major war fighting operations.
However,If the United Kingdom uses aircraft carriers to provide airpower during major warfighting operations it will have no air bases to protect from ballistic missiles.
The second most vulnerable target for conventional ballistic missile attack is a port.
Such facilities are highly congested when an armed force is deploying in to theatre.
Ships are expensive but their cargoes are worth far more,both before and after they have been unloaded.
A ballistic missile attack on a port has a high probability of causing significant material loss and also of disrupting land force operations.
However,a navy which can put an army ashore without the need for a port has little to fear from land attack ballistic missiles.
At present the United Kingdom does not possess the ability to land it's army without port facilities.
It is therefore faced with the choice of acquiring a ballistic missile defence capability or of acquiring the ability to land it's army without a port.
Theatre range ship attack ballistic missiles do not at present pose a threat.
Only China is currently developing such a system and that is not yet operational.
The massive cost of the network needed to make such a system viable dictates that only the wealthiest of nations could attempt to field such a system and even then it would be many years before such systems became operational outside China.
It is highly unlikely that The United Kingdom will have the need to singlehandedly go to war against China within range of Chinese land based missiles.
Consequently there is no need to field a counter to these systems at present,though there may be a need in the long term.
There is no need for an anti-ballistic missile system to engage strategic nuclear missiles.
There is a need for an anti-ballistic missile system to protect the ports through which the army must be landed at present.
If landing ships capable delivering the army of over the beach were to enter service then there would be no such requirement.
There is a requirement for an anti-ballistic missile system to protect air bases at present.
If the new Queen Elizabeth class carriers enter service with a full capability air wing then there will be no such requirement.
There is no requirement at present for an anti-ballistic missile system to protect ships at sea.
If such anti-ship systems proliferate in future decades then such a requirement may materialise.
At present the United Kingdom does have a requirement for an anti-ballistic missile system.
It does not however have such a system.
However,such an upgrade to the destroyer fleet,including missiles is likely to cost approximately £500 Million.
Given current financial difficulties it is difficult to imagine such funds being found.
It is also questionable whether it is worth while tying up such high value assets in the anti-ballistic missile role when the need for such a system could be negated for decades at least by replacing the current sealift fleet with more flexible ships capable of landing the army over a beach.